A Hero-Jet Driven Porous Spherical Hydrostatic Gas Bearing Gyro

Abstract

The gyro system under consideration consists of a hollow porous sphere supported in a hydrostatic gas-lubricated spherical bearing. High pressure gas leaking into the sphere through the pores from the bearing film pressurizes the inside of the sphere and is exhausted from a series of Hero jets located around the equator to counter the viscous drag from the bearing and maintain a constant speed. Analysis has been presented for predicting equilibrium speed, flow rates, and stiffness for axisymmetric condition as a function of various dimensionless system parameters representing porosity, drive nozzles, inlet feeding holes, supply pressure, etc. Effects of the various system parameters on the performance of the gyro are illustrated. A preliminary feasibility study has been made for a wide angle and a narrow angle bearing. It is found that the small angle bearing is less subject to lock-up without significant loss of stiffness, but suffers from a lower speed and a less efficient gas utilization. A particular design will represent a compromise between stiffness and speed.